Coward! Villain!This is a cockpit phrase; all cocks, except gamecocks, being called dunghills.
“Out, dunghill! darst thou brave a nobleman?”
That is, Dare you, a dunghill cock, brave a thoroughbred gamecock?
Thou hast it, ad dunghill, at thy fingers' ends. To this Holofernes replies: “Oh, I smell false Latin; `dunghill' for `unguem.' ” (Shakespeare: Love's Labour's Lost, v. I.)
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894